DFI Installation Study

Every year the Deep Foundation Institute in the United States has a project fund to support innovative studies in a number of areas identified by the technical committees as being critical to the deep foundation industry.

Following a competitive submission process, the project titled “Comparison of Impact versus Vibratory Piles” was awarded in March 2014. This project was supported by both the marine foundations and driven piling technical committees, with the technical research being coordinated by Dr. Paul Doherty Managing Director at GDG.

Recognising that current engineering standards have been based on impact driven piles and do not explicitly consider the effect of vibratory installation, this research project was proposed to assess the impact of the installation procedure on long-term pile performance.

Scope of work:

The focus of the research was to assess whether the axial and lateral resistance of driven piles are affected by the hammer type, whether vibratory or traditional impact hammers. The project compiled published literature and recently completed case studies to establish any trends in pile performance with different hammer types.

Furthermore, to expand the database of relevant case studies, all practitioners in the deep foundations industry were encouraged to submit details of projects where the relative merits of impact and vibratory piles can be quantified.

A database was compiled that included the results of the survey with contractors from the US, South America and Europe. The findings demonstrated that impact piling has a positive impact on the pile performance when compared to vibratory installed piles. However the factors influencing these results, including the hammer characteristics and operating conditions, complicate the interpretation of the pile behaviour.